Laser pulse signal processing device, communication device, and communication method

Abstract

The invention provides a laser pulse signal processing device, a communication device and a communication method. The laser pulse signal processing device comprises: a controller for mapping an information bit stream to be transmitted to obtain a modulation symbol (410); and a spatial light modulator for receiving the modulation symbol from the controller and modulating the modulation symbol onto the laser pulse signal to obtain a modulated laser pulse signal, the modulated laser pulse signal being different from the OAM mode of the laser pulse signal (420). Based on the device, the data signal to be transmitted is modulated to the OAM mode of the laser pulse to be sent based on an OAM modulation mode. Because the waveform and the OAM mode are two different dimensions of the laser pulse, mutual interference between the communication performance and the measurement performance of the laser radar can be reduced as much as possible, thereby improving the communication rate.

Description

Laser pulse signal processing device, communication device and communication method Technical Field

[0001] The present application relates to the field of communication and measurement, and in particular to a laser pulse signal processing device, a communication device, and a communication method. Background Art

[0002] Lasers are widely used in communications and measurement due to their excellent monochromaticity, directionality, and strong anti-interference capabilities. In everyday applications, both laser communications and lidar measurements are accomplished with the help of lasers. Therefore, further research is needed to determine how to use the same laser light source for both communication and measurement.

[0003] Currently, lidar primarily uses a method for communication by modulating the waveform of the laser pulse used for measurement, modulating the data signal to be transmitted onto the laser pulse's intensity domain, i.e., the waveform. This communication method can introduce noise interference, affecting the signal-to-noise ratio (SNR), and thus reducing the communication rate to, for example, kilobits per second (kbps), which is insufficient for high-speed communication.

[0004] Summary of the Invention

[0005] The present application provides a laser pulse signal processing device, a communication device, and a communication method, in order to improve the communication rate of laser communication.

[0006] In a first aspect, the present application provides a laser pulse signal processing device, comprising a controller and a spatial light modulator; the controller is used to map an information bit stream to be transmitted to obtain a modulation symbol; the spatial light modulator is used to receive the modulation symbol from the controller; and modulate the modulation symbol onto a laser pulse signal to obtain a modulated laser pulse signal, wherein the modulated laser pulse signal has an orbital angular momentum (OAM) mode different from that of the laser pulse signal.

[0007] Based on the above-mentioned laser pulse signal processing device, the data signal to be transmitted is modulated into the spatial mode domain of the laser pulse based on the OAM modulation method, more specifically, it is sent on the OAM mode. Among them, the OAM mode is a property of the transverse mode of the laser pulse. The transverse mode describes the energy distribution on the laser spot and can be expressed as the distribution of the light field intensity on the cross section of the laser pulse. Since the waveform and the OAM mode are two different dimensions of the laser pulse, this method can minimize the impact between the communication function and the ranging function of the laser radar, thereby reducing the potential noise interference caused by the radar waveform and improving the signal-to-noise ratio of the communication. Since the communication rate is positively correlated with the signal-to-noise ratio of the communication, the communication rate can be improved.

[0008] In combination with the first aspect, in some possible implementations of the first aspect, the laser pulse signal processing device also includes: a laser and an emitting optical system; the laser is used to generate the laser pulse signal; and the emitting optical system is used to emit the modulated laser pulse signal.

[0009] In combination with the first aspect, in certain possible implementations of the first aspect, the information bit stream includes at least one information bit, and the modulation symbol includes at least one topological charge corresponding to the at least one information bit; the controller is specifically used to: map the at least one information bit based on a mapping relationship to obtain at least one topological charge; the mapping relationship includes a correspondence between a value carried by at least one bit and the topological charge, and different values ​​carried by each bit correspond to the presence or absence of a topological charge.

[0010] The controller can map the information bit stream to be transmitted based on a certain mapping relationship to obtain modulation symbols.

[0011] In combination with the first aspect, in some possible implementations of the first aspect, the laser pulse signal is a Gaussian light signal, and the modulated laser pulse signal is a Laguerre Gaussian (LG) light signal; the controller is further configured to: based on the maximum topological charge number l max , determine at least one topological charge; the maximum topological charge l max It is determined based on the predefined receiving aperture, the scanning angle resolution of the laser pulse signal processing device and the predefined working distance, and the maximum topological charge number l max Greater than or equal to 2.

[0012] The modulated laser pulse signal can be an LG optical signal, and the mode order of the LG optical signal includes the topological charge. To determine the topological charge included in the modulation symbol, the maximum topological charge l can be determined based on the limiting conditions. max The limiting conditions may include a predefined receiving aperture, a scanning angle resolution of the laser pulse signal processing device, and a predefined working distance. max -1 and (-l max +1) is not zero, the maximum topological charge number l max Greater than or equal to 2.

[0013] In conjunction with the first aspect, in some possible implementations of the first aspect, each topological charge in the at least one topological charge satisfies: less than or equal to l max -1, and greater than or equal to (-l max +1), and each topological charge is a non-zero number.

[0014] This part except l max and -l max The topological charge other than is the topological charge obtained by mapping the information bit stream, and this part of the topological charge carries the information to be transmitted.

[0015] In combination with the first aspect, in some possible implementations of the first aspect, the modulation symbol includes: max or -l max One of them.

[0016] In practical applications, the topological charge number l corresponding to different modulated laser pulse signals may be different, so the beam waist radius of the modulated laser pulse signal may be inconsistent, which may affect the communication device's reception and recognition of the modulated laser pulse signal. Therefore, the topological charge number included in the modulation symbol needs to include l max or -l max One of them is to keep the beam waist radius of the modulated laser pulse signal constant, which is beneficial to the reception and recognition of the communication device.

[0017] In combination with the first aspect, in some possible implementations of the first aspect, the laser pulse signal is one of a plurality of laser pulse signals emitted within a sampling period of the laser pulse signal processing device.

[0018] The laser pulse signal processing device samples a spatial position in one sampling period, and can emit one or more laser pulse signals in one sampling period.

[0019] In combination with the first aspect, in some possible implementations of the first aspect, at least two laser pulse signals among the multiple laser pulse signals are used to carry different modulation symbols, and the different modulation symbols are obtained based on modulation of different information bit streams.

[0020] Multiple laser pulse signals within a sampling period can be used to carry the same modulation symbol or different modulation symbols.

[0021] In combination with the first aspect, in some possible implementations of the first aspect, the controller is further used to: determine a scanning period based on a preset scanning area and a scanning angle resolution of the laser pulse signal processing device, wherein the start time of the scanning period coincides with the rising edge or falling edge of the controller's clock signal, and the end time of the scanning period coincides with the rising edge or falling edge of the controller's clock signal; generate a timing control signal based on the scanning period, the timing control signal being used to control the transmission time of the information to be transmitted; and send the timing control signal to the spatial light modulator.

[0022] For a controller, every action is triggered by the edge of a clock signal. If the start and end times of a scan cycle don't coincide with the rising or falling edge of the controller's clock signal, the controller may not be able to effectively control the switching of information between two adjacent scan areas. To avoid this problem, the controller can adjust the start and end times of the scan cycle to coincide with the rising or falling edge of the controller's clock signal.

[0023] In combination with the first aspect, in some possible implementations of the first aspect, the spatial light modulator is specifically used to modulate the modulation symbol into multiple laser pulse signals based on a timing control signal, and the multiple laser pulse signals are laser pulse signals emitted within a scanning period.

[0024] The spatial light modulator modulates the modulation symbols onto the laser pulse signal under the instruction of the timing control signal. That is, the modulation symbols corresponding to the information to be transmitted are modulated onto the laser pulse signal corresponding to the transmission time of the information to be transmitted.

[0025] In combination with the first aspect, in some possible implementations of the first aspect, the information bit stream is obtained by encoding the information to be transmitted, and the information to be transmitted includes information for requesting one-to-one communication; the controller is also used to: after scanning the communication device, conduct one-to-one communication with the communication device.

[0026] The information transmitted by the laser pulse signal processing device in the form of broadcast may include information requesting one-to-one communication. Then, after scanning the communication device, the laser pulse signal processing device may perform one-to-one communication with the communication device.

[0027] In combination with the first aspect, in some possible implementations of the first aspect, the laser pulse signal processing device also includes a receiving optical system; the receiving optical system is used to receive an echo signal, which is a signal returned by the modulated laser pulse signal after reaching an obstacle.

[0028] In addition to communication capabilities, the laser pulse signal processing device also has measurement capabilities. Therefore, the laser pulse signal processing device may also include a receiving optical system. This receiving optical system is used to receive the echo signal, which is the signal returned by the modulated laser pulse signal after it reaches an obstacle.

[0029] It should be understood that the transmitting optical system and the receiving optical system of the laser pulse signal processing device can be the same optical system or two different optical systems.

[0030] In the second aspect, the present application provides a communication device, including a receiving optical system, a photosensitive array and a demodulator; the receiving optical system is used to receive a modulated laser pulse signal from a laser pulse signal processing device; the photosensitive array is used to detect the distribution of light field intensity from the modulated laser pulse signal; the demodulator is used to identify the distribution of light field intensity and obtain modulation symbols; and is used to demodulate based on the modulation symbols to obtain an information bit stream.

[0031] The communication device receives the laser pulse signal emitted by the laser pulse signal processing device to achieve communication with the laser pulse signal processing device. The receiving optical system of the communication device may include a lens system and a filter to receive the modulated laser pulse signal and detect the distribution of the light field intensity in the modulated laser pulse signal. Since the information to be transmitted is modulated onto the OAM mode of the laser pulse and sent, and the OAM mode is a property of the transverse mode of the laser pulse, it can be expressed as the distribution of the light field intensity on the cross section of the laser pulse. Therefore, the communication device can receive information by detecting the distribution of the light field intensity in the modulated laser pulse signal.

[0032] Furthermore, existing communication devices used for laser communication include photosensitive arrays that have low resolution requirements, generally being able to sense the overall intensity of the light field. Compared to existing communication devices used for laser communication, the communication device provided in this application has a higher resolution photosensitive array, capable of sensing the intensity distribution of the light field at different locations on the photosensitive array, thereby better detecting the distribution of the light field intensity.

[0033] In combination with the second aspect, in some possible implementations of the second aspect, the modulation symbol includes at least one topological charge number, and the demodulator is specifically used to: obtain an information bit stream based on the mapping relationship and the modulation symbol, the information bit stream including at least one information bit, the mapping relationship including a correspondence between a value carried by at least one bit and a topological charge number, and different values ​​carried by each bit correspond to the presence or absence of a topological charge number.

[0034] The role of the demodulator is to identify the distribution of the light field detected by the photosensitive array, and based on the distribution of the light field, identify the modulation symbols modulated onto the laser pulse signal, and then further demodulate the modulation symbols to obtain the information bit stream to complete the information transmission.

[0035] The demodulator can be, for example, a digital signal processing (DSP) chip, which can identify the distribution of light field intensity based on a convolutional neural network to identify the modulation symbol. Since the receiving optical system of the communication device may not be completely aligned with the lidar, the received modulated laser pulse signal may show non-affine distortion. The use of a convolutional neural network helps the demodulator better identify the distribution of light field intensity. After identifying the modulation symbol, the demodulator can demodulate the modulation symbol to obtain an information bit stream based on the mapping relationship mentioned above.

[0036] In a third aspect, the present application provides a laser radar, comprising a laser pulse signal processing device as in any possible implementation of the first aspect above.

[0037] In a fourth aspect, the present application provides a communication system, comprising a laser pulse signal processing device as in any possible implementation of the first aspect above, and a communication device as in any possible implementation of the second aspect above.

[0038] In a fifth aspect, the present application provides a communication method applied to a laser pulse signal processing device, which includes a controller and a spatial light modulator; the method includes: the controller maps the information bit stream to be transmitted to obtain a modulation symbol; the spatial light modulator receives the modulation symbol from the controller; and modulates the modulation symbol onto the laser pulse signal to obtain a modulated laser pulse signal, wherein the modulated laser pulse signal is different from the OAM mode of the laser pulse signal.

[0039] In combination with the fifth aspect, in some possible implementations of the fifth aspect, the laser pulse signal processing device also includes a laser and an emitting optical system; the method also includes: the laser generates a laser pulse signal; and the emitting optical system emits the modulated laser pulse signal.

[0040] In combination with the fifth aspect, in some possible implementations of the fifth aspect, the information bit stream includes at least one information bit, and the modulation symbol includes at least one topological charge corresponding to the at least one information bit; the controller maps the information bit stream to be transmitted to obtain the modulation symbol, including: mapping the at least one information bit based on the mapping relationship to obtain at least one topological charge; the mapping relationship includes a correspondence between the value carried by at least one bit and the topological charge, and the different values ​​carried by each bit correspond to the presence or absence of a topological charge.

[0041] In conjunction with the fifth aspect, in some possible implementations of the fifth aspect, the laser pulse signal is a Gaussian light signal, and the modulated laser pulse signal is an LG light signal. The method further includes: based on the maximum topological charge number lmax , determine at least one topological charge; the maximum topological charge l max It is determined based on the predefined receiving aperture, the scanning angle resolution of the laser pulse signal processing device and the predefined working distance, and the maximum topological charge number l max Greater than or equal to 2.

[0042] In conjunction with the fifth aspect, in some possible implementations of the fifth aspect, each topological charge in the at least one topological charge satisfies: less than or equal to l max -1, and greater than or equal to (-l max +1), and each topological charge is a non-zero number.

[0043] In conjunction with the fifth aspect, in some possible implementations of the fifth aspect, the modulation symbol includes: max or -l max One of them.

[0044] In combination with the fifth aspect, in some possible implementations of the fifth aspect, the laser pulse signal is one of a plurality of laser pulse signals emitted within a sampling period of the laser pulse signal processing device.

[0045] In combination with the fifth aspect, in some possible implementations of the fifth aspect, at least two laser pulse signals among the multiple laser pulse signals are used to carry different modulation symbols, and the different modulation symbols are obtained based on different information bit stream modulations.

[0046] In combination with the fifth aspect, in some possible implementations of the fifth aspect, the method also includes: determining a scanning period based on a preset scanning area and a scanning angle resolution of a laser pulse signal processing device, wherein the start time of the scanning period coincides with the rising edge or falling edge of the clock signal of the controller, and the end time of the scanning period coincides with the rising edge or falling edge of the clock signal of the controller; generating a timing control signal based on the scanning period, wherein the timing control signal is used to control the transmission time of the information to be transmitted; and sending the timing control signal to the spatial light modulator.

[0047] In combination with the fifth aspect, in some possible implementations of the fifth aspect, the spatial light modulator is specifically used to modulate the modulation symbol into multiple laser pulse signals based on a timing control signal, and the multiple laser pulse signals are laser pulse signals emitted within a scanning period.

[0048] In combination with the fifth aspect, in some possible implementations of the fifth aspect, the information bit stream is obtained by encoding the information to be transmitted, and the information to be transmitted includes information for requesting one-to-one communication; the method also includes: after scanning the communication device, performing one-to-one communication with the communication device.

[0049] In combination with the fifth aspect, in some possible implementations of the fifth aspect, the laser pulse signal processing device also includes a receiving optical system; the method also includes: the receiving optical system receives an echo signal, and the echo signal is a signal returned when the modulated laser pulse signal reaches an obstacle.

[0050] In a sixth aspect, the present application provides a communication method, which is applied to a communication device, comprising a receiving optical system, a photosensitive array and a demodulator; the method comprises: the receiving optical system receives a modulated laser pulse signal from a laser pulse signal processing device; the photosensitive array detects the distribution of light field intensity from the modulated laser pulse signal; the demodulator identifies the distribution of light field intensity and obtains modulation symbols; and demodulates based on the modulation symbols to obtain an information bit stream.

[0051] In combination with the sixth aspect, in some possible implementations of the sixth aspect, the modulation symbol includes at least one topological charge, and the information bit stream is obtained based on the modulation symbol demodulation, including: based on the mapping relationship and the modulation symbol, the information bit stream is obtained, the information bit stream includes at least one information bit, the mapping relationship includes the correspondence between the value carried by at least one bit and the topological charge, and the different values ​​carried by each bit correspond to the presence or absence of a topological charge.

[0052] In the seventh aspect, the present application provides a computer-readable storage medium having a computer program stored thereon, which, when executed on a computer, enables the methods in the above-mentioned fifth and sixth aspects and any possible implementation of the fifth and sixth aspects to be implemented.

[0053] In an eighth aspect, the present application provides a computer program product, which includes: a computer program (also referred to as code, or instructions), which, when the computer program is run, enables the methods in the above-mentioned fifth and sixth aspects and any possible implementation methods of the fifth and sixth aspects to be implemented.

[0054] It should be understood that the third to eighth aspects of the present application correspond to the technical solutions of the first and second aspects of the present application, and the beneficial effects achieved by each aspect and the corresponding feasible implementation methods are similar and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] FIG1 is a schematic diagram of a usage scenario of a laser radar provided in an embodiment of the present application;

[0056] FIG2 is a schematic diagram of the structure of a laser pulse signal processing device provided in an embodiment of the present application;

[0057] FIG3 is a schematic diagram of the cross-sectional light field intensity distribution of the LG optical signal provided in an embodiment of the present application;

[0058] FIG4 is a flow chart of a communication method applied to a laser pulse signal processing device according to an embodiment of the present application;

[0059] FIG5 is a diagram of p=0 and l provided in an embodiment of the present application. max Schematic diagram of the light field intensity distribution of the cross section of the modulated laser pulse signal when is 2;

[0060] FIG6 is a schematic diagram of a laser radar scanning scene provided in an embodiment of the present application;

[0061] FIG7 is a schematic diagram of adjusting the scanning period according to an embodiment of the present application;

[0062] FIG8 is a schematic diagram of the structure of a communication device provided in an embodiment of the present application;

[0063] FIG9 is a flow chart of a communication method applied to a communication device provided in the present application. DETAILED DESCRIPTION

[0064] The technical solution in this application will be described below with reference to the accompanying drawings.

[0065] Lasers are widely used in communications and measurement due to their excellent monochromaticity, directionality, and strong anti-interference capabilities. In everyday applications, laser radar (LiDAR) can be used for measurement tasks, while lasers can be used for communication tasks. Since both LiDAR and laser communication functions are achieved with lasers, researchers are exploring how to use the same laser light source for both communication and measurement.

[0066] FIG1 is a schematic diagram of a usage scenario of a laser radar provided in an embodiment of the present application. As shown in FIG1 , the scenario shows a laser radar and a communication device. The laser radar emits a modulated laser pulse signal carrying information. After the modulated laser pulse signal hits the communication device, diffuse reflection occurs. The laser radar receives the reflected echo signal and calculates the distance to the communication device based on the time of flight (ToF) method through the echo signal. At the same time, the communication device receives the modulated laser pulse signal emitted by the laser radar and obtains the information carried in the modulated laser pulse signal.

[0067] Currently, lidars modulate the data signal to be transmitted onto the waveform of laser pulses. This method can interfere with the lidar's communication and measurement capabilities. Interference can introduce more noise, reducing the signal-to-noise ratio (SNR). Consequently, communication rates are slow, reaching the order of kilobits per second (kbps), which is insufficient for high-speed communication.

[0068] In view of this, the present application proposes a laser pulse signal processing device, a communication device, a laser radar and a communication system. The laser pulse signal processing device can modulate the data signal to be transmitted onto the OAM mode of the laser pulse based on the OAM modulation method and send it. Among them, the OAM mode is a property of the transverse mode of the laser pulse. The transverse mode describes the energy distribution on the laser spot and can be expressed as the distribution of the light field intensity on the cross section of the laser pulse. Since the waveform and the OAM mode are two different dimensions of the laser pulse, this method can minimize the impact between the communication function and the ranging function of the laser radar, thereby reducing the potential noise interference caused by the radar waveform and improving the signal-to-noise ratio of the communication. The communication rate is positively correlated with the signal-to-noise ratio of the communication, so the communication rate is improved.

[0069] Figure 2 is a schematic diagram of the structure of a laser pulse signal processing device provided in an embodiment of the present application. As shown in Figure 2, the laser pulse signal processing device includes a controller and a spatial light modulator.

[0070] Among them, the controller can map the information bit stream to obtain modulation symbols; and the spatial light modulator can modulate the modulation symbols onto the laser pulse signal, and the modulated laser pulse signal is different from the OAM mode of the laser pulse signal.

[0071] Based on the above-mentioned laser pulse signal processing device, the data signal to be transmitted is modulated onto the OAM mode of the laser pulse based on the OAM modulation method and sent. Among them, the OAM mode is a property of the transverse mode of the laser pulse. The transverse mode describes the energy distribution on the laser spot and can be expressed as the distribution of the light field intensity on the cross section of the laser pulse. Since the waveform and the OAM mode are two different dimensions of the laser pulse, this method can minimize the impact between the communication function and the ranging function of the laser radar, thereby reducing the potential noise interference caused by the radar waveform and improving the signal-to-noise ratio of the communication. The communication rate is positively correlated with the signal-to-noise ratio of the communication, so the communication rate can be improved.

[0072] Optionally, the laser pulse signal processing device may further include a laser and a transmitting optical system. The laser is used to generate a laser pulse signal; and the transmitting optical system is used to transmit the modulated laser pulse signal.

[0073] In the laser pulse signal processing device, a laser is used to generate a laser pulse signal. The cross-sectional dimensions of the laser pulse signal generated by the laser satisfy a Gaussian function, resulting in a Gaussian light signal. A spatial light modulator modulates the laser pulse signal based on a modulation symbol from a controller to obtain a modulated laser pulse signal. The modulated laser pulse signal can be a Hermite-Gaussian light signal or a LG light signal, which is not limited in this application.

[0074] The difference between a Hermite-Gaussian optical signal and an LG optical signal is that the pattern of a Hermite-Gaussian optical signal is the solution of a wave equation in a Cartesian coordinate system, while the pattern of an LG optical signal is the solution of a wave equation in a cylindrical coordinate system. The following uses an LG optical signal as an example to illustrate this.

[0075] The LG optical signal mainly includes two mode orders, p is used to represent the number of radial nodes, and l can be called the topological charge number. The values ​​of p and l are generally integers.

[0076] Figure 3 is a schematic diagram of the cross-sectional optical field intensity distribution of an LG optical signal provided by an embodiment of the present application. As shown in Figure 3, it can be seen that when p = 0, the larger the value of l, the larger the beam waist radius of the LG optical signal; when l = 0, the larger the value of p, the larger the beam waist radius of the LG optical signal, and the more radial nodes of the cross-sectional optical field intensity of the LG optical signal.

[0077] The relationship between the beam waist radius of the LG optical signal and the beam waist radius of the Gaussian optical signal at the same transmission distance is shown in Formula 1:

[0078]

[0079] Where z is the transmission distance of the optical signal, ω LG (z) is the beam waist radius of the LG optical signal with a transmission distance of z, and ω(z) is the beam waist radius of the Gaussian optical signal with a transmission distance of z. As can be seen from Formula 1, at the same distance, the larger the absolute value of l, the larger ω LG (z) is also larger; at the same distance, the larger the absolute value of p is, the larger ω is. LG (z) is also larger. And because the absolute value of p is preceded by a multiple of "2", p is more important to ω than l. LG (z) has a greater impact.

[0080] The relationship between the beam waist radius ω(z) of a Gaussian light signal and the transmission distance z is shown in Formula 2:

[0081]

[0082] Where ω0 is the beam waist radius of the Gaussian light signal at the emission plane, and λ is the wavelength of the light signal. Equation 2 shows that, given a given beam waist radius at the emission plane and the wavelength of the light signal, the longer the transmission distance, the larger the beam waist radius of the Gaussian light signal.

[0083] The laser radar provided in the embodiments of this application has a predefined operating distance. Within this predefined operating distance, the beam waist radius of the LG optical signal should be as small as possible. This is because if the beam waist radius of the LG optical signal is too large, it may be larger than the receiving aperture of the communication device, making it unable to fully receive the optical signal, affecting communication quality. It may also be limited by the scanning angle resolution of the laser radar, causing two adjacent optical signals emitted by the laser radar during scanning to partially overlap, making the two adjacent optical signals indistinguishable and thus affecting communication quality.

[0084] The modulation symbols from the controller mentioned above can be used to instruct the spatial light modulator to modulate the Gaussian optical signal into an LG optical signal with different cross-sectional optical field intensity distributions. The modulation symbols can include two mode orders, p and l, which affect the cross-sectional optical field intensity distribution of the LG optical signal. That is, the modulation symbols can include both p and l, only p without l, or only l without p. This application does not limit this.

[0085] However, in practical applications, since the beam waist radius of the LG optical signal needs to be controlled to be as small as possible, the modulation symbol can be made to exclude the mode order p, which has a greater impact on the beam waist radius, and only include the topological charge l. In other words, p = 0 in the modulation symbol.

[0086] Therefore, the following description is made by taking the case where the modulation symbol only includes the topological charge number l as an example.

[0087] The laser pulse signal processing device may execute the communication method shown in FIG4 , wherein the communication method 400 includes:

[0088] Step 410: The controller maps the information bit stream to be transmitted to obtain modulation symbols; and

[0089] In step 420 , the spatial light modulator receives the modulation symbol from the controller and modulates the modulation symbol onto the laser pulse signal to obtain a modulated laser pulse signal. The modulated laser pulse signal has an OAM mode different from that of the laser pulse signal.

[0090] The communication method 400 is described in detail below.

[0091] In step 410, the controller may map the transmitted information bit stream based on a certain mapping relationship to obtain modulation symbols. The mapping relationship here includes a correspondence between the value carried by at least one bit and the topological charge, where different values ​​carried by each bit correspond to the presence or absence of a topological charge.

[0092] Therefore, before determining the mapping relationship, the topological charge number included in the modulation symbol can be determined first. The topological charge number included in the modulation symbol can be determined based on the maximum topological charge number lmax to confirm.

[0093] Since the beam waist radius of the LG optical signal has a maximum value within the predefined working distance, the topological charge l also has a maximum value, that is, the maximum topological charge l max . l max It can be calculated based on Formula 1 and Formula 2, as well as the receiving aperture of the communication device and the scanning angle resolution of the laser radar mentioned above. The maximum value of the topological charge l calculated by the receiving aperture of the communication device and the maximum value of the topological charge l calculated by the scanning angle resolution of the laser radar may be different. Finally, the positive value with the smallest absolute value among the different results is taken as the maximum topological charge l. max .

[0094] It should be understood that the laser radar can know the receiving aperture of the communication device in advance. This can be achieved, for example, by: all communication devices have the same receiving aperture size, the laser radar and the communication device comply with the same communication protocol, and the communication protocol specifies the receiving aperture size of the communication device; or, all communication devices have different receiving aperture sizes, the laser radar and the communication device comply with the same communication protocol, and the communication protocol specifies a minimum receiving aperture size for the communication device, and the minimum value specified in the protocol is used as the receiving aperture size for the communication device. This application does not limit the implementation method.

[0095] The scanning angle resolution and predefined working distance are the working parameters of the laser radar, which can also be understood by the laser radar itself. Therefore, based on the above two limiting conditions, the laser radar can predetermine the maximum topological charge number l max .

[0096] After determining the maximum topological charge l max Thereafter, the topological charge number included in the modulation symbol is determined next.

[0097] The topological charge included in the modulation symbol can be composed of two parts. One part is the topological charge obtained by mapping the information bit stream. This part of the topological charge carries the information to be transmitted. The value range of this part of the topological charge satisfies less than or equal to l max -1, and greater than or equal to (-l max +1) and is not zero; the other part is irrelevant to the information bit stream and is a fixed topological charge. This part of the topological charge includes and only includes l max or -l max One of them.

[0098] It can be seen from formula 1 that the absolute value of the topological charge number l is positively correlated with the beam waist radius of the LG optical signal. That is to say, under the condition that other conditions are constant, the larger the absolute value of the topological charge number l, the larger the beam waist radius of the LG optical signal. In practical applications, the topological charge number l corresponding to different modulated laser pulse signals may be different, so the beam waist radius of the modulated laser pulse signal may not be uniform, which may affect the communication device's reception and recognition of the modulated laser pulse signal. Therefore, the topological charge number included in the modulation symbol needs to include l max or -l max One of them is to keep the beam waist radius of the modulated laser pulse signal constant, which is beneficial to the reception and recognition of the communication device.

[0099] From the above conditions of topological charge, we can see that l max -1 and (-l max +1) are not zero, so the maximum topological charge l max The value should be greater than or equal to 2.

[0100] For example, if the maximum topological charge l max is 2, then the topological charge included in the modulation symbol is 1, -1 and 2, or 1, -1 and -2; if the maximum topological charge is l max If is 3, the number of topological charges included in the modulation symbol is 1, -1, 2, -2, and 3, or 1, -1, 2, -2, and -3.

[0101] After determining the topological charge included in the modulation symbol, the information bit stream to be transmitted can be mapped according to a mapping relationship. The mapping relationship includes a correspondence between a value carried by at least one bit and the topological charge, where different values ​​carried by each bit correspond to the presence or absence of a topological charge.

[0102] Table 1 shows a possible correspondence between the value of each bit and the topological charge in an information bit stream of N bits.

[0103] Table 1

[0104]

[0105] As shown in Table 1, when the first bit is 0, the topological charge takes a null value, that is, it does not include 1; when the first bit is 1, the topological charge includes 1; when the second bit is 0, the topological charge takes a null value, that is, it does not include -1; when the second bit is 1, the topological charge includes -1; and so on; when the N-1th bit is 0, the topological charge takes a null value, that is, it does not include l max-1; when the N-1th bit is 1, the topological charge includes l max -1; when the Nth bit is 0, the topological charge takes a null value, that is, it does not include (-l max +1); when the Nth bit is 1, the topological charge includes (-l max +1).

[0106] For example, if the maximum topological charge l max The topological charge number is 2, and the topological charge number included in the modulation symbol is 1, -1, and 2. Among the three topological charge numbers included in the modulation symbol, 1 and -1 are related to the information bit stream and are used to carry the information bit stream to be transmitted; 2 is independent of the information bit stream and is a fixed topological charge number.

[0107] In the above example, the two topological charges 1 and -1 are used to carry the information bit stream to be transmitted, and thus can be mapped to the information bit stream including two bits. A possible mapping relationship is shown in Table 2.

[0108] Table 2

[0109]

[0110] As shown in Table 2, when the first bit is 0, the topological charge takes a null value, that is, it does not include 1; when the first bit is 1, the topological charge includes 1; when the second bit is 0, the topological charge takes a null value, that is, it does not include -1; when the second bit is 1, the topological charge includes -1.

[0111] There are four cases, namely, both bits are 0; the first bit is 1 and the second bit is 0; the first bit is 0 and the second bit is 1; and both bits are 1.

[0112] In the first case, if both bits are 0, the topological charge included in the modulation symbol is 2; in the second case, if the first bit is 1 and the second bit is 0, the topological charge included in the modulation symbol is 1 and 2; in the third case, if the first bit is 0 and the second bit is 1, the topological charge included in the modulation symbol is -1 and 2; in the fourth case, if both bits are 1, the topological charge included in the modulation symbol is 1, -1 and 2.

[0113] It should be understood that the above mapping relationship is only an example, and this application does not limit the specific mapping relationship.

[0114] The controller may map the information bit stream based on the above mapping relationship to obtain modulation symbols.

[0115] In step 420, the spatial light modulator receives the modulation symbol from the controller and modulates the modulation symbol onto the laser pulse signal. The modulated laser pulse signal differs from the OAM mode of the laser pulse signal. The OAM mode is a property of the transverse mode of the laser pulse, which can be expressed as the distribution of the light field intensity across the cross section of the laser pulse signal. The OAM mode of the modulated laser pulse signal obtained by using different modulation symbols also varies.

[0116] The OAM mode of the modulated laser pulse signal obtained by the spatial light modulator according to the modulation symbol can be expressed as the coherent superposition of the distribution of the light field intensity on the cross section of the laser pulse signal corresponding to each topological charge number included in the modulation symbol.

[0117] Figure 5 shows the case where p=0 and l max Schematic diagram of the light field intensity distribution of the cross section of four modulated laser pulse signals that can be obtained by the spatial light modulator based on the modulation symbol when is 2.

[0118] As shown in Figure 5, (a) in Figure 5 is a schematic diagram of the cross-sectional optical field intensity distribution of the modulated laser pulse signal when the topological charge number included in the modulation symbol is 2. In this case, the cross-sectional optical field intensity distribution of the laser pulse signal is the same as the cross-sectional optical field intensity distribution of the LG optical signal with l=2; (b) in Figure 5 is a schematic diagram of the cross-sectional optical field intensity distribution of the modulated laser pulse signal when the topological charge number included in the modulation symbol is 1 and 2. In this case, the cross-sectional optical field intensity distribution of the laser pulse signal is a coherent superposition of the cross-sectional optical field intensity distribution of the LG optical signal with l=1 and the cross-sectional optical field intensity distribution of the LG optical signal with l=2; (c) in Figure 5 is a schematic diagram of the cross-sectional optical field intensity distribution of the laser pulse signal when the topological charge number included in the modulation symbol is - 1 and 2, a schematic diagram of the cross-sectional optical field intensity distribution of the modulated laser pulse signal. In this case, the cross-sectional optical field intensity distribution of the laser pulse signal is a coherent superposition of the cross-sectional optical field intensity distribution of the LG optical signal with l=-1 and the cross-sectional optical field intensity distribution of the LG optical signal with l=2; (d) in FIG5 is a schematic diagram of the cross-sectional optical field intensity distribution of the modulated laser pulse signal when the topological charge number included in the modulation symbol is 1, -1 and 2. In this case, the cross-sectional optical field intensity distribution of the laser pulse signal is a coherent superposition of the cross-sectional optical field intensity distribution of the LG optical signal with l=1, the cross-sectional optical field intensity distribution of the LG optical signal with l=-1 and the cross-sectional optical field intensity distribution of the LG optical signal with l=2.

[0119] As can be seen from the above examples, when the topological charge included in the modulation symbol is different, the cross-sectional optical field intensity distribution of the modulated laser pulse signal is different, and the OAM mode of the modulated laser pulse signal is also different. In other words, the lidar modulates the data signal to be transmitted onto the OAM mode of the laser pulse.

[0120] Figure 6 shows a possible scenario for using the above solution for communication and measurement. The LiDAR transmits information in a broadcast format while scanning in all directions, and can transmit different information to different scanning areas. For example, first information is transmitted to the first scanning area, second information is transmitted to the second scanning area, and third information is transmitted to the third scanning area.

[0121] The range of each of the above scanning areas can be pre-defined by the user. For example, the range of the first scanning area is ∠A, the range of the second scanning area is ∠B, and the range of the third scanning area is ∠C. The controller can determine the scanning period based on the scanning area and the scanning angle resolution of the laser radar. For example, the scanning angle resolution is R° / T, where T is the time of a sampling period of the laser radar, R° is the angle scanned by the laser radar in one sampling period, and the sampling period is the time required for sampling a spatial position when the laser radar performs ranging. The scanning period can be calculated from the range of the scanning area and the scanning angle resolution of the laser radar. For example, the first scanning period of the first scanning area is equal to ∠A÷(R° / T), the second scanning period of the second scanning area is equal to ∠B÷(R° / T), and the third scanning period of the third scanning area is equal to ∠C÷(R° / T).

[0122] However, determining the scan cycle this way can present a problem: the calculated start and end times of the scan cycle may not coincide with the rising or falling edge of the controller's clock signal. Each controller action is triggered at the edge of the clock signal. If the start and end times of the scan cycle do not coincide with the rising or falling edge of the controller's clock signal, the controller may not be able to effectively control the switching of information between two adjacent scan areas.

[0123] To avoid the above-mentioned problems, the controller can adjust the start and end times of the scanning cycle so that they coincide with the rising edge or falling edge of the controller's clock signal. The adjustment method can be as shown in (a) of Figure 7, where the start and end times of each scanning cycle are adjusted to coincide with the rising edge or falling edge of the previous clock signal; or it can be as shown in (b) of Figure 7, where the start and end times of each scanning cycle are adjusted to coincide with the rising edge or falling edge of the nearest clock signal. This application does not limit this.

[0124] After adjusting the start and end times of the scanning period, the controller can generate a timing control signal based on the adjusted scanning period and send the timing control signal to the spatial light modulator. The timing control signal can be used to control the sending time of the information to be transmitted.

[0125] The spatial light modulator modulates the modulation symbols onto the laser pulse signal under the instruction of the timing control signal, that is, the modulation symbols corresponding to the information to be transmitted are modulated onto the laser pulse signal corresponding to the transmission time of the information to be transmitted.

[0126] Furthermore, a laser radar samples a spatial location during a sampling cycle. The laser radar can emit one or more laser pulse signals during a sampling cycle. Furthermore, multiple laser pulse signals within a sampling cycle can carry the same modulation symbol or different modulation symbols. This application also does not impose any limitations on this.

[0127] In addition to communication capabilities, lidar also has measurement capabilities. Therefore, lidar also includes a receiving optical system. This receiving optical system is used to receive echo signals, which are the return signals of the modulated laser pulse signal after it reaches an obstacle. It should be understood that the transmitting and receiving optical systems of a lidar can be the same optical system with different functions, or they can be two different optical systems.

[0128] After the laser radar receives the echo signal through the receiving optical system, it can calculate the distance to the obstacle based on the ToF method. The obstacle can be a communication device or any other object.

[0129] Based on this approach, the data signal to be transmitted is modulated onto the OAM mode of the laser pulse using OAM modulation. Because the waveform and OAM mode are two different dimensions of the laser pulse, this approach minimizes interference between the lidar's communication and measurement performance, thereby increasing the communication rate.

[0130] Figure 8 is a schematic diagram of the structure of a communication device provided in an embodiment of the present application. As shown in Figure 8, the communication device includes a receiving optical system, a photosensitive array, and a demodulator.

[0131] Among them, the receiving optical system can receive the modulated laser pulse signal from the laser pulse signal processing device; the photosensitive array can detect the distribution of the light field intensity from the modulated laser pulse signal; the demodulator can identify the distribution of the light field intensity and obtain the modulation symbol; and the information bit stream can be demodulated based on the modulation symbol.

[0132] The communication device may execute the communication method shown in Figure 9, where the communication method 900 includes steps 910 to 930. The communication method 900 is described in detail below.

[0133] In step 910 , the receiving optical system receives the modulated laser pulse signal from the laser pulse signal processing device.

[0134] The receiving optical system of the communication device may include a lens system and a filter for receiving the modulated laser pulse signal.

[0135] In step 920, the photosensitive array detects the distribution of light field intensity from the modulated laser pulse signal.

[0136] The communication device receives the laser pulse signal emitted by the laser pulse signal processing device to achieve communication with the laser pulse signal processing device. The receiving optical system of the communication device may include a lens system and a filter to receive the modulated laser pulse signal and detect the distribution of the light field intensity in the modulated laser pulse signal. Since the information to be transmitted is modulated onto the OAM mode of the laser pulse and sent, and the OAM mode is a property of the transverse mode of the laser pulse, it can be expressed as the distribution of the light field intensity on the cross section of the laser pulse. Therefore, the communication device can receive information by detecting the distribution of the light field intensity in the modulated laser pulse signal.

[0137] Furthermore, existing communication devices used for laser communication include photosensitive arrays that do not require high resolution; generally, they are sufficient to sense the overall intensity of the light field. Compared to existing communication devices used for laser communication, the communication device provided in the embodiments of the present application has a higher resolution photosensitive array, capable of sensing the intensity distribution of the light field at different locations on the photosensitive array, thereby better detecting the distribution of the light field intensity.

[0138] In step 930, the demodulator identifies the distribution of the light field intensity and obtains modulation symbols; and demodulates based on the modulation symbols to obtain an information bit stream.

[0139] The role of the demodulator is to identify the distribution of the light field detected by the photosensitive array, and based on the distribution of the light field, identify the modulation symbols modulated onto the laser pulse signal, and then further demodulate the modulation symbols to obtain the information bit stream to complete the information transmission.

[0140] The demodulator can be, for example, a DSP chip. The DSP chip can use a convolutional neural network to identify the distribution of light field intensity and thus recognize the modulation symbol. Because the communication device's receiving optical system may not be perfectly aligned with the lidar, the received modulated laser pulse signal may exhibit non-affine distortion. Using a convolutional neural network helps the demodulator better identify the distribution of light field intensity.

[0141] After identifying the modulation symbols, the demodulator can demodulate the modulation symbols to obtain an information bit stream based on the mapping relationship mentioned above.

[0142] Optionally, the information transmitted by the laser radar in the form of broadcast may include information requesting one-to-one communication. Then, after scanning the communication device, the laser radar can communicate one-to-one with the communication device.

[0143] A possible application scenario is as follows: in a home, a lidar is part of a smart home control center, and the communication device is a robot vacuum. During scanning, the lidar broadcasts a message requesting one-to-one communication. Upon receiving this message, the communication device stops moving and aligns its receiving optical system as closely as possible with the lidar. The lidar uses its ranging capability to detect the contours of the communication device and adjusts the direction of its transmitting optical system accordingly, aligning it with the device's receiving optical system, thereby establishing one-to-one communication with the device.

[0144] The above application scenarios are only examples, and this application does not limit the specific application scenarios.

[0145] For the laser radar provided in this embodiment, the achievable communication rate is the number of bits of the information bit stream carried by the laser pulse signal in one sampling period divided by the time of one sampling period.

[0146] When the predefined working distance is 40 meters, the predefined receiving aperture is 5 cm, and other hardware conditions are not restricted, the maximum topological charge number l max =10. Therefore, there are 18 topological charges to carry the information bit stream to be transmitted. If only one laser pulse signal is included in a sampling period, the laser pulse signal can carry 18 bits within a sampling period. Current lidar can achieve a sampling frequency of 160kHz. Calculations show that within a communication distance of 40 meters, the communication rate can reach 2.88 megabits per second (Mbps), far exceeding the kbps-level communication rate of existing technologies.

[0147] According to the method provided in the present application, the present application also provides a computer-readable storage medium, which stores program code. When the program code runs on a computer, the communication method described in the embodiment corresponding to Figure 4 or Figure 9 is executed.

[0148] According to the method provided by the present application, the present application further provides a computer program product, the computer program product comprising: computer program code. When the computer program code is executed on a computer, the communication method described in the embodiment corresponding to FIG. 4 or FIG. 9 is executed.

[0149] The technical solutions provided in this application can be implemented in whole or in part through software, hardware, firmware, or any combination thereof. When implemented using software, they can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the processes or functions described in this application are generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via a wired connection (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium accessible by a computer or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., a floppy disk, hard disk, magnetic tape), an optical medium (e.g., a digital video disc (DVD), or a semiconductor medium.

[0150] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A laser pulse signal processing device, characterized in that: include: A controller, configured to map the information bit stream to be transmitted to obtain modulation symbols; a spatial light modulator, configured to receive the modulation symbols from the controller; The modulation symbol is modulated onto the laser pulse signal to obtain a modulated laser pulse signal, wherein the modulated laser pulse signal has an OAM mode different from that of the laser pulse signal.

2. The device according to claim 1, wherein The laser pulse signal processing device further includes: A laser, configured to generate the laser pulse signal; The transmitting optical system is used to transmit the modulated laser pulse signal.

3. The device according to claim 1 or 2, characterized in that The information bit stream includes at least one information bit, and the modulation symbol includes at least one topological charge corresponding to the at least one information bit; The controller is specifically used to: map the at least one information bit based on a mapping relationship to obtain the at least one topological charge; the mapping relationship includes a correspondence between the value carried by at least one bit and the topological charge, and different values ​​carried by each bit correspond to the presence or absence of a topological charge.

4. The device according to claim 3, characterized in that The laser pulse signal is a Gaussian light signal, and the modulated laser pulse signal is a Laguerre-Gaussian LG light signal; The controller is also used to: Based on the maximum topological charge l max , determine the at least one topological charge; the maximum topological charge l max It is determined based on a predefined receiving aperture, a scanning angle resolution of the laser pulse signal processing device, and a predefined working distance, and the maximum topological charge number l max Greater than or equal to 2.

5. The device according to claim 3 or 4, characterized in that Each topological charge in the at least one topological charge satisfies: less than or equal to l max -1, and greater than or equal to (-l max +1), and each topological charge is a non-zero number.

6. The device according to claim 5, characterized in that The modulation symbol also includes l max or -l max One of them.

7. The device according to any one of claims 1 to 6, characterized in that The laser pulse signal is one of a plurality of laser pulse signals emitted within a sampling period of the laser pulse signal processing device.

8. The device according to claim 7, characterized in that At least two laser pulse signals among the multiple laser pulse signals are used to carry different modulation symbols, and the different modulation symbols are obtained based on modulation of different information bit streams.

9. The device according to any one of claims 1 to 8, characterized in that The controller is also used for: Determining a scanning period according to a preset scanning area and a scanning angle resolution of the laser pulse signal processing device, wherein a start time of the scanning period coincides with a rising edge or a falling edge of a clock signal of the controller, and an end time of the scanning period coincides with a rising edge or a falling edge of the clock signal of the controller; generating a timing control signal based on the scanning period, wherein the timing control signal is used to control a transmission time of information to be transmitted; The timing control signal is sent to the spatial light modulator.

10. The device according to claim 9, wherein The spatial light modulator is specifically configured to modulate the modulation symbol into a plurality of laser pulse signals based on the timing control signal, where the plurality of laser pulse signals are laser pulse signals emitted within the scanning period.

11. The device according to claim 10, wherein The information bit stream is obtained by encoding the information to be transmitted, and the information to be transmitted includes information for requesting one-to-one communication; The controller is also used for: After scanning a communication device, one-to-one communication is performed with the communication device.

12. The device according to any one of claims 2 to 11, characterized in that The laser pulse signal processing device further includes: The receiving optical system is used to receive an echo signal, where the echo signal is a signal returned when the modulated laser pulse signal reaches an obstacle.

13. A communication device, characterized in that: include: a receiving optical system for receiving the modulated laser pulse signal from the laser pulse signal processing device; A photosensitive array, used to detect the distribution of light field intensity from the modulated laser pulse signal; The demodulator is used to identify the distribution of the light field intensity to obtain modulation symbols; and to demodulate based on the modulation symbols to obtain an information bit stream.

14. The device according to claim 13, wherein The modulation symbol includes at least one topological charge number, and the demodulator is specifically configured to: Based on the mapping relationship and the modulation symbol, the information bit stream is obtained, the information bit stream includes at least one information bit, the mapping relationship includes a correspondence between the value carried by at least one bit and the topological charge number, and the different values ​​carried by each bit correspond to the presence or absence of a topological charge number.

15. A laser radar, characterized in that: The method comprises the laser pulse signal processing device according to any one of claims 1 to 12.

16. A communication system, characterized in that: The device comprises the laser pulse signal processing device according to any one of claims 1 to 12, and the communication device according to any one of claims 13 to 14.

17. A communication method, characterized in that: Applicable to a laser pulse signal processing device, the laser pulse signal processing device comprising a controller and a spatial light modulator; The method comprises: The controller maps the information bit stream to be transmitted to obtain modulation symbols; The spatial light modulator receives the modulation symbol from the controller and modulates the modulation symbol onto the laser pulse signal to obtain a modulated laser pulse signal, wherein the modulated laser pulse signal has an OAM mode different from that of the laser pulse signal.

18. The method according to claim 17, wherein The laser pulse signal processing device also includes a laser and a transmitting optical system; The method further comprises: The laser generates a laser pulse signal; The transmitting optical system transmits the modulated laser pulse signal.

19. The method according to claim 17 or 18, wherein: The information bit stream includes at least one information bit, and the modulation symbol includes at least one topological charge corresponding to the at least one information bit; The controller maps the information bit stream to be transmitted to obtain modulation symbols, including: Mapping the at least one information bit based on the mapping relationship to obtain the at least one topological charge; The mapping relationship includes a corresponding relationship between a value carried on at least one bit and a topological charge, and different values ​​carried on each bit correspond to the presence or absence of a topological charge.

20. The method according to claim 19, wherein The laser pulse signal is a Gaussian light signal, and the modulated laser pulse signal is a Laguerre-Gaussian (LG) light signal. The method further includes: Based on the maximum topological charge l max , determine the at least one topological charge; the maximum topological charge l max It is determined based on a predefined receiving aperture, a scanning angle resolution of the laser pulse signal processing device, and a predefined working distance, and the maximum topological charge number l max Greater than or equal to 2.

21. The method according to claim 19 or 20, wherein: Each topological charge in the at least one topological charge satisfies: less than or equal to l max -1, and greater than or equal to (-l max +1), and each topological charge is a non-zero number.

22. The method according to claim 21, wherein The modulation symbol also includes l max or -l max One of them.

23. The method according to any one of claims 17 to 22, characterized in that The laser pulse signal is one of a plurality of laser pulse signals emitted within a sampling period of the laser pulse signal processing device.

24. The method according to claim 23, wherein At least two laser pulse signals among the multiple laser pulse signals are used to carry different modulation symbols, and the different modulation symbols are obtained based on modulation of different information bit streams.

25. The method according to any one of claims 17 to 24, characterized in that The method further comprises: Determining a scanning period according to a preset scanning area and a scanning angle resolution of the laser pulse signal processing device, wherein a start time of the scanning period coincides with a rising edge or a falling edge of a clock signal of the controller, and an end time of the scanning period coincides with a rising edge or a falling edge of the clock signal of the controller; generating a timing control signal based on the scanning period, wherein the timing control signal is used to control a transmission time of information to be transmitted; The timing control signal is sent to the spatial light modulator.

26. The method of claim 25, wherein: The spatial light modulator is specifically configured to modulate the modulation symbol into a plurality of laser pulse signals based on the timing control signal, where the plurality of laser pulse signals are laser pulse signals emitted within the scanning period.

27. The method according to claim 26, wherein The information bit stream is obtained by encoding the information to be transmitted, and the information to be transmitted includes information for requesting one-to-one communication; The method further comprises: After scanning a communication device, one-to-one communication is performed with the communication device.

28. The method according to any one of claims 18 to 27, wherein The laser pulse signal processing device further includes a receiving optical system; The method further comprises: The receiving optical system receives an echo signal, which is a signal returned when the modulated laser pulse signal reaches an obstacle.

29. A communication method, characterized in that: Applied to a communication device, the communication device includes a receiving optical system, a photosensitive array, and a demodulator; the method includes: The receiving optical system receives the modulated laser pulse signal from the laser pulse signal processing device; The photosensitive array detects the distribution of light field intensity from the modulated laser pulse signal; The demodulator identifies the distribution of the light field intensity to obtain modulation symbols; and demodulates based on the modulation symbols to obtain an information bit stream.

30. The method of claim 29, wherein: The modulation symbol includes at least one topological charge, and the demodulating based on the modulation symbol to obtain an information bit stream includes: Based on the mapping relationship and the modulation symbol, the information bit stream is obtained, the information bit stream includes at least one information bit, the mapping relationship includes a correspondence between the value carried by at least one bit and the topological charge number, and the different values ​​carried by each bit correspond to the presence or absence of a topological charge number.

31. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 17 to 28 or the method according to any one of claims 29 to 30 is executed.

32. A computer program product, characterized in that The invention comprises a computer program which, when being executed, causes the method according to any one of claims 17 to 28 to be performed, or the method according to any one of claims 29 to 30 to be performed.

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